Egosoft Interactive FAQ

No, with GOG you don't have to install any client to install, update or play your games. You download all the games' or patch installers or bonus content from a dedicated GOG download page and install them then. Please see this FAQ article for reference.

If you don't want to do that manually, there is a game client called GOG Galaxy, which provides features similar to the Steam client. To learn more about GOG Galaxy, please visit its dedicated website.